Drawing press



192 Aug 16, 7 F. J. RODE DRAWING PRESS Filed Feb. 9. 1924 Patented Aug. 16, 1927.

UNITED STATES y l 1,638,881 PATENT OFFICE.

FRIEDRICH J. RODE, OF CHICAGO, ILLINOIS, ASSIGNOB TO MARQUETTE TOOL & IANU` FAC'FURING CO., OF CHICAGO, ILLINOIS, .A CORPORATION Ol' ILLINOIS.

DRAWING Pansa'.

` Application iled February This invention relates in general to improvements in drawing presses but more particularly to a press of this character adapted for drawing metal shapes or shells and in which presses there is provided blank gripping or holding means, generally termed a draw rin which co-operates vwith the plunger of t e press for gripping and holding the material while the latter is being shaped over the forming die, the said draw ring being influenced in its operation by a cushioning device.

One of the serious disadvantages of many cushioning devices for sheet metal drawing l5 dies is that they follow the punch on the upward or return movement thereof with the result that there will be created in the ress what is commonly known in the tra e as back lash or back kick which not only injures the machine and shortens the life thereof but is in many other respects very objectionable.

It is one of the objects of the presentjnvention to overcome these difficulties and object-ions and to provide improved accurate and simple means to contro the upward or return movement of the draw ring at-will, and allow it to return at a certain predetermined point in the cycle of operation of the device.

If the return movement of the draw ring is retarded with respect to the return of the female punch during the upward stroke of the press, then the ressure is relieved from this female die and) consequently the crank and clutch of the press will also be relieved of this pressure, which is an important advantage.

To the attainment of these ends and the accomplishment of other new and useful objects as will ap ear, the invention consists in the features of) novelty in substantially the construction, combination and arrangement of the several parts hereinafter more fully described and claimed and shown in the accompanying drawing illustrating this invention an in which Figure l is a vertical, longitudinal sectional view of a portion of a draw press having a cushioning device constructed in accordance with the principles of this invention applied thereto, and showing the parts in one position.

Figure 2 is a view similar to Figure 1 showing the parts in another position.

9, 1924. Serial No. 691,653.

Referring more particularly tothe drawlng the numeral 10 designates the bed or y bolster plate of a draw press, 11 al recipro- `pating ram or plunger, 12 the female die member which .is connected and moves with the ram or plunger, 13 the male die member which is supported upon the bed or bolster plate 10, 14 a draw ring which co-operates with the die member 12 for gripping and holding the work 15, 16 the supporting pins for the draw ring 14, and 17 a pin late u on which the pins 16 rest. All o the a ove referred to parts are of the ordinary and well-known construction in presses of this character.

Supported below the'bolster plate 10 in any desired or suitable manner preferably by means of bars or rods 17 secured by one end to the bed plate is a cross bar or member 18 upon which rests a closed cylinder 19. If desired the cylinder may be secured to the member 18 in any desired or suitable manner such as by means of fastening devices 20.

The cylinder 19 is preferably spaced for some distance below the bed plate 10 and the bore of the cylinder may be of any desired or suitable diameter.

Reciprocable within the cylinder is a piston 21 whichhas connected with it a piston rod 22 that extends through the head of the cylinder and a suitable bushing or packing 23. The free end of the piston rod 22 is preferably secured to the pin plate 17 in any desired or suitable manner such as by means of fastening devices 24.

The piston rod 22 is of any desired diameter and serves the purpose of reducing the piston area on one side of the piston so that the area of the piston on that side will be less than the piston area on the opposite side, for a purpose to be hereinafter set forth.

Fluid pressure is supplied to the cylinder 19 beneath the piston 21 from any suitable source of suppl and preferably through a pipe 25. The pipe 25 is also connected with 100 the top portion of the cylinder on the opposite s1de of the piston, preferably through the medium of a by-pass passage 26, which discharges into the upper end of the cylinder as at 27. Within this passage 26 is 106 disposed a suitable vthree-Way valve 28 for controlling the passage and for cutting off or establishing communication between the upper portion of the cylinder and the lower portion thereof. This valve 28 embodies a 110 the esca e of fluid from the top of the cylinder. he valve is adapted to be adjusted into another position as shown in Figure 2, so as to re-establish communication between the pressure supply pipe 25 and the top of the cylinder and to shut off communication between the top ofthe cylinder` on one side of the piston and the atmosphere.

The valve 32 is adapted to beactuated in any desired or suitable manner preferably by means of a bar or rod 34 connected with a movable part of the press and which bar or rod has adjustably connected with it fingers or tappets 35-,36, each adapted to engage an arm or lever 37 connected with the valve 32, so that when the parts are in the position shown in Figure 1,'when the bar or rod 34 is lowered the linger 35 will shift the lever 37 to rotate the valve to the position shown in Figure 2.

'When the parts move from the position in Figure 2 back to the position shown in Figure 1, the finger 36 w1ll engage .the lever 37 and rotate the valve 32 from the position shown in Figure 2 back to the position shown in Figure 1.

By adjustably mounting the fingers 35 36 on the rod 34, it will be manifest that the time of operationl or engagement of the respective fingers 35-36 with the lever 37 may be varied so that the valve v32 may be actuated at any predetermined point in the cycle of operation of the press. f

In operation and with the parts in the position shown in Figure 1, which is the initial position of the draw ring and the cushioning device therefor, the draw ring Y 14 will be depressed with respect to the die or forming block 13 when the ram or plunger 11 is lowered, causing the draw ring, through the medium of the pins 16, pin plate 17, piston rod 22 and piston 21 to operate against the lluid pressure in the cylinder 19. on the under side of the piston 21. As soon as the drawing operation is completed and just as the parts approach the positionshown in Figure 2, the valve 32 will be shifted from the position shown in Figure 1, to the position shown in Figure 2, thereby permitting the lluid pressure from the supply pipe 25 to be sup lied to the cylinder 19 on the upper side oi) the piston 21. Inasmuch as the piston area on the upper side of the piston 21 is less than the piston area on the lower side thereof, the 4fluid pressure against the upper side of the piston will be reduced which will result in a pressure being exerted upon the lower face of the piston 21, which is slightly in excess of the pressure' exerted upon the upper side thereof, the excess pressure being determined by the diamicient pressure on the lower face of the pis'- ton in excess of the pressure on the upper face thereof, to return the piston, back lash upon the press when the crank passes over the center on the upstroke will be obviated.

Obviously the piston rod 32 may be of any desired diameter according to the reduction of the piston area-that it is desired to produce on that side of the piston.

It will also be further manifest that the lingers 35-36 may be adjusted upon the rod 34 to operate the valve 32 at any desired time in the operation of the press.

The area of the upper surface of the piston 21 may be reduced with respect to the areaof the lower face of the piston so that just enough pressure may be exerted upon the lower face of the piston on theI upstroke to overcome the weight and friction of the parts and if desired Aenough pressure may be exerted upon the lower face of the piston on the upstroke to strip the work or shaped article from the male die or forming block 13.

While the preferred form of the invention has been herein shown and described it is to be understood that various changes may be made in the details of construction and in the combination and arrangement of the several parts, within the scope of the claims, without departing from the spirit of this invention.

What is claimed as new is:-

1. A drawing press including a lunger, a blank holder co-operating therewith to clamp the work, and fluid pressure cushioning means for the blank holder, said cushioning means including a cylinder and piston relatively movable one with relation to the other, means for supplying fluid pressure to the cylinder on one side of the piston, and means for directing the fluid to the opposite side of the piston, the opposite faces of the piston being of different areas.

2. A drawing press includin a plunger, a blank holder co-operating t erewith to clamp the work, fluid ressure cushioning means for the blank hol er, said cushioning means including a cylinder and piston relatively movable one with relation to the other, means for supplying fluid pressure to the cylinder on one side of the piston, and means for directing the fluid to the opposite side of the piston, the surfaces on opposite sides of the piston and upon which the fluid pressure operates being of different areas.

3. A drawing press including a plunger, a blank holder co-operating therewith to clamp the work, fluid pressure cushioning means for the blank; holder and against which pressure the blank holder operates during one direction of its movement, and means for subjecting such cushioning means to the same fluid pressure during the movement of the blank holder in the opposite direction, the area of the surface upon which the fluid pressure operates during one direction of movement of the blank holder being greater than the area of the surface on which the fluid pressure acts during the movement of the blank holder in the op osite direction.

4. A drawing press inclu ing a plunger, a blank holder co-operating therewith to clamp the work, fluid pressure cushioning means for the blank holder and against which pressure the blank holder operates during one direction of its movement, means for subjecting such cushioning means ,to the same fluid pressure during the movement of the blank holder in the opposite direction, the area of the surface upon which the fluid pressure operates during one direction of movement of the blank holder bein greater than the area of the surface on w ich the fluid pressure acts during the movement of the blank holder in the opposite direction, and means for controlling the action of the said fluid pressure against one of the said surfaces to retard the return of the blank holder.

5. A drawing press including a recipro cable plunger. a blank holder co-operating therewith to clamp the work, fluid pressure cushioning means for the blank holder and against the pressure of which fluid pressure the blank holder is operated by the said plunger, and means for relieving the plunger of such fluid pressure on the up or return stroke of the plunger, the said means including automatically actuated valve mechanism.

6. A drawing ress including a reciprocable plunger, a Iblank holder co-operating therewith to clamp the work, fluid pressure cushioning means for the blank holder and against the pressure of which fluid pressure the blank holder is operated by the said plunger, means responsive in its operation to the operation of the plunger for relieving the plunger of such fluid pressure, the said means including automatically actuating valve mechanism, and means whereby the time of actuation of the said valve mechanism in the cycle of operation of the plunger may be varied at will.

In testimony whereof I have signed my name to this specification, on this 5th day of February, A. D. 1924.

FREDRICH J. RODE. 

